The present invention relates generally to safety devices, and more particularly, to a specially constructed rear view mirror adapted for use on motorcycles and related vehicles.
The continuing concern with vehicle safety has now expanded to the point that there is a substantial and continuing interest in the safety of not only automobiles, but also motorcycles and related vehicles. Along these lines, significant efforts have been made to improve the so-called "crossworthiness" of motorcycles and the like vehicles, so as to avoid injury to the operator or passengers thereon.
While it is well known that motorcycles are in some respects safer than automobiles, insofar as they possess favorable potential for rapid maneuvering, and particularly, rapid braking, there is no question that motorcycles, in other respects, present safety hazards that are much greater than those associated with automobiles. In certain classes of motorcycle accidents, it has been found that motorcycle operators who might otherwise have been uninjured, or not injured seriously, have in fact been injured, and in some cases seriously, by contact with certain parts of the motorcycle itself. For example, it is generally accepted that, upon colliding with a fixed object, a motorcycle has a tendency to rotate upward and forwardly from the rear, tending to throw the passenger forward along or just over the gas tank, and ultimately, over the handlebars.
Certain constructions of safety devices have been made which take account of this problem, including the construction of windshields described in my patent application Ser. No. 685,707, filed May 12, 1976 now Pat. No. 4,082,345. This windshield construction is intended to avoid serious injuries to a motorcycle operator in a collision, where the rider is propelled forward and into contact with one or more of the braces which serve to hold the windshield in place.
A hazard of a similar kind exists with respect to motorcycle rear view mirrors which, in most if not all states, are required by law to be installed on motorcycles. While such mirrors are advantageous for their primary purpose, that is, to provide visibility to the rear of the motorcycle, such mirrors also present an injury hazard to a rider who may be thrown forward against and partially over such mirrors. In certain cases, a rider who might otherwise have escaped injury has been injured by receiving a blow in the face, eyes, shoulders, abdomen, or the like from a mirror mounted on the handlebars.
In automobiles, certain suggestions for breakaway or pivotable type mirror constructions have been made, and a certain number of these proposals have met with some success. However, the situation presented in automobiles and motorcycles are significantly different in at least several important respects.
First, a motorcycle mirror is almost always mounted in the wind stream of the vehicle, that is, it is mounted on the handlebars near the hand grips and extends either upwardly or upwardly and outwardly therefrom so that it provides a path of sight over the shoulders of the operator and to the rear thereof. As a result of being disposed in the air stream of the vehicle, a motorcycle mirror may not be loosely or pivotally mounted as can permissibly be the case with an automobile rear view mirror. Motorcycle mirrors, in normal use, are subjected to wind forces which may approach and even exceed velocities of 70-80 miles per hour or more. Accordingly, the concept of a pivotally mounted mirror has not proven generally successful for use with motorcycles subjected to reasonable speeds in traffic.
Another situation which is peculiar to many, if not all motorcycles, is the presence of vibration on a level which is much greater than that imposed upon an automobile.
For example, an automobile's mirror is commonly mounted on the windshield, dashboard, or headliner of the automobile. These parrts are isolated from the engine by rubber engine mounts, body mounts, and the like. Moreover, automobile engines are commonly well-balanced six and eight cylinder engines.
Motorcycles, on the other hand, often have the handlebars fastened directly to the frame just above the front wheel. Accordingly, wheel imbalance as well as engine vibration is transmitted quite directly to the handlebars and to the mirrors mounted thereon. In motorcycles of single and twin cylinder configurations, as well as a certain number of three and four cylinder motorcycles, engine vibrations are a common problem.
The extent of this problem is further aggravated because of the wide range of engine speed often encountered by small displacement engines. For example, it is not uncommon for ordinary motorcycle engines in completely stock condition to be adapted to operate at speeds up to 9,000 to 10,000 rpm or more. Consequently, loose or pivotal mounting of either the motorcycle mirror or the portion which in turn mounts the mirror to the handlebar simply does not prove satisfactory in use.
Those attempts which have been made to mount the mirror loosely so that it would be pushed out of the way in the event of an accident have failed for at least one and commonly two reasons. In the first place, loose mounting of the mirror invariably results in the mirror moving to a position in which it fails to serve its intended purpose. Secondly, as is most commonly the case, the mirror is in turn mounted on an assembly which includes means for mounting the clutch lever and the front brake lever. In those modern motorcycles, using hydraulic disc front brakes, the hydraulic reservoir is also mounted on the mirror mounting apparatus. Consequently, loose mounting of this entire subassembly with respect to the handlebar would be exceptionally dangerous from the standpoint of permitting the brake lever to rotate out of the position in which the driver is accustomed to find it. Also, such rotation raises the problem of moving the hydraulic controls for the front brake into an inoperative position. Accordingly, the mirror mounts have customarily been affixed quite rigidly to the handlebars, but such mounting, in the event of an accident creates a serious problem.
Other suggestions have been made in the prior art concerning safety mirror construction, at least one of which involves providing an area of weakness or reduced cross section within the threaded portion of the mirror mount. However, a solution of this sort is not practical for motorcycle applications. This is because, in use, motorcycle mirrors are commonly loosened from their locking nuts so as to be rotatable to an alternate position for loading and unloading the motorcycle, and for moving it into and out of storage and service areas. Consequently, the nut locking the mirror in place is locked and unlocked frequently. Moreover, because of the problems of vibration and wind force, it is customary to tighten the lock nut down with considerable force. Experienced motorcycle mechanics and riders periodically check the lock nuts on the mirrors to insure that they are sufficiently tight so that the mirror does not loosen in use and become worthless when it might be needed.
Therefore, constructing the threaded area of the mirror stem with a breakaway or cutdown portion is not satisfactory, since this would reduce the strength of the mirror where substantial strength is most needed.
In the design of a new motorcycle mirror embodying the safety feature referred to above, it is also possible to incorporate another desirable concept, namely, the production of a single mirror which will act as either a left- or right-handed mirror.
A problem which confronts accessory manufacturers and dealers is the need to stock both left- and right-handed mirrors for motorcycles. This need is particularly disadvantageous when there is no predetermined demand for either right- or left-handed mirrors, and no indication that the demand for one style or the other will predominate over any period of time or under any particular set of circumstances. Accordingly, an advantageous mirror is one which may be installed on either the left or right hand side of the motorcycle without compromising its ability to extend upwardly and outwardly from a mounting point on the handlebar end so as to provide both sturdy and convenient mounting and good visibility.
As is the case with auto parts, significant economy of manufacturing and stocking can be achieved if a single part can be adapted to both right and left hand locations.
In prior art motorcycle mirrors, whether or not purportedly safety mirrors, the mirror head has been mounted to the remote end of the stem by a swivel joint located generally centrally and toward the lower portion of the front surface of the rearview mirror. As a consequence, mirrors which are designed so as to extend both upwardly and outwardly, and to have their head portion affixed to the stem on the front surface of the mirror are not interchangeable as right and left hand mirrors.
Accordingly, distributors and manufacturers must make right and left hand mirrors and dealers and distributors must stock right and left hand mirrors. An advantage to one form of mirror made according to the present invention is that the same mirror may be made to serve both right and left hand installations even though the stem extends both upwardly and then upwardly and outwardly. This is accomplished by placing a pivot ball and socket or other pivot type joint in a sidewall portion of the mirror which is intentionally designated to have a head with a measurably forwardly extending sidewall portion. When the mirror is moved from a left to a right hand installation, or vice versa, the mirror head is merely rotated about its horixontal axis.
Bearing in mind the foregoing disadvantages of prior art mirrors and the failure to solve the problem of an economical but safe motorcycle mirror adapted to be highly useful even under adverse conditions, it is an object of the present invention to provide an improved motorcycle safety mirror.
It is a further object of this invention to provide a breakaway type mirror in which the mounting portion will separate from the mirror head and stem upon impact of a predetermined force.
A still further object is to provide a motorcycle safety mirror which will be sturdy and reliable in use, but which is constructed so as to break away upon receipt of a sharp blow under impact.
Another object is to provide a motorcycle which includes a zone or area of weakness at a predetermined point, but which does not compromise its strength for purposes of a firm mounting.
Another object is to provide a motorcycle safety mirror which is compatible with existing mounting units.
A still further object is to provide a motorcycle mirror which can be locked in place using significant torque but which will readily be broken upon impact of a predetermined magnitude.
Another object is to provide a motorcycle mirror having a stem with a groove of a diameter less than that of the root diameter of the threaded end of the mirror stem, and which may in one embodiment include relatively sharp inner margins for concentrating stresses in this area.
Another object is to provide a motorcycle safety mirror having a head, an elongated stem, a threaded end portion adapted to cooperate with the locking nut thereon, and in which a groove providing a breakaway or weakened zone is provided just above the upper surface of the lock nut when the mirror is in the normal position of use.
A still further object is to provide a motorcycle mirror wherein the stem, preferably a breakaway type stem, enters the mirror head assembly from the side so as to permit favorable positioning of the mirror and, preferably to permit the mirror to be positioned so that the same mirror can be used for both right and left hand sides of the motorcycle.
A still further object is to provide a mirror which is mounted so as to have the head portion thereof pivotally mounted to one end of the stem in a manner such that the mirror can rotate about a substantially horizontal axis with the mirror preferably having a ball and socket mounting to provide this feature.
The foregoing objects and advantages are achieved in practice by providing a mirror which in the normal position of use includes a stem having a threaded lower end portion received within a mounting bracket, a lock nut engaged with the threads and securing the stem to the mounting bracket, a zone of reduced cross section just above the top of the lock nut, and a mirror head disposed at the top of the stem and mounted for pivotal movement thereon.
Other objects are achieved by providing a motorcycle mirror constructed and arranged so that the head portion includes a stem receiving portion extending generally perpendicular to the plane of the reflective surface so that the mirror can be rotatable about a horizontal axis and thus made to serve as either a right- or left-handed mirror.
The manner in which these and other objects and other advantages of the invention are achieved in practice will become more clearly apparent when reference is made to the accompanying detailed description of the preferred embodiments of the invention set forth by way of example, and shown in the accompanying drawings where like reference numbers indicate corresponding parts throughout.